The present invention relates, in general, to electronics, and more particularly, to methods of forming semiconductor devices and structure.
In the past, various circuits and methods were used to implement charging circuits for battery-powered appliances such as vacuum cleaners, power tools, and other cordless appliances. In many applications, the charging circuit and the battery were integrated into the battery-powered appliance. One typical implementation utilized a diode and a resistor in series as a simple and inexpensive battery charging circuit. Generally, these circuits were very inefficient and even consumed excessive power after the battery was completely charged.
Accordingly, it is desirable to have a battery charging circuit that is efficient, that has a low cost, and that may be integrated into a battery-powered appliance.
For simplicity and clarity of illustration, elements in the figures are not necessarily to scale, and the same reference numbers in different figures denote the same elements. Additionally, descriptions and details of well-known steps and elements are omitted for simplicity of the description. As used herein current carrying electrode means an element of a device that carries current through the device such as a source or a drain of an MOS transistor or an emitter or a collector of a bipolar transistor or a cathode or anode of a diode, and a control electrode means an element of the device that controls current through the device such as a gate of an MOS transistor or a base of a bipolar transistor. Although the devices are explained herein as certain N-channel or P-Channel devices, a person of ordinary skill in the art will appreciate that complementary devices are also possible in accordance with the present invention. It will be appreciated by those skilled in the art that the words during, while, and when as used herein are not exact terms that mean an action takes place instantly upon an initiating action but that there may be some small but reasonable delay between the reaction that is initiated by the initial action.